Native Tree Society BBS

Mycorrhizal fungi are extremely beneficial for trees, and in most instances are required for the tree to prosper. Mycorrhizae allow trees to absorb more water and nutrients, notably phosphorous from the soil. Additionally, mycorrhizae help defend trees against pathogens and nematodes, can suppress competing organisms, boost regeneration survival, and even allow trees to communicate to each other during times of distress. The type of mycorrhizae depends on the plant. More info if interested:

http://mycorrhizas.info/index.html
http://mycorrhizae.com/wp-content/uploa ... Plants.pdf
http://onlinelibrary.wiley.com/doi/10.1 ... 5/abstract

Ectomycorrhiza and the willow oak This willow oak first stood out to me last fall when I noticed Pisolithus tintorius, a very useful generalist ecto underneath the tree. Since then I have revisited the tree a handful of times. I have observed ~12 different ecto species associated with it, along with 3 saprobic species on its roots/fallen branches, and one foliar rust. Macro fungi found on the surface is usually only a fraction of the total population, making me speculate how many mutualistic partners this one tree really has.

Ecto species- (Genus is correct, species may not be)
Amanita flavorubescens
Amanita vaginata (grissete)
Boletus ornatipes
Cantherellus minor
Hygrocybe marginata (role unknown, could be saprobic)
Lactarius allardii
Lactarius sanguifluus
Pisolithus tintorius
Russula spp. 1
Russula spp. 2
Russula virescens-like species
Scleroderma polyrhizum

Saprobic species
Daldina concentrica
Ganoderma lucidum (Reishi)
Meripilus spp.

Foliar rust
Cronartium quercuum
Endomycorrhiza and the dogwood

Additionally I wanted to see how many endo partners a tree may have. Endo fungi produce spores in the soil so no mushroom is produced. To observe endo species you must collect soil from around the roots and sieve/decant to isolate the spores for observation under a microscope. Identification is extremely difficult, with the majority of species not even described to science. I chose a tiny dogwood sapling in the forest to dig up, curious to see how many associations it may have. There were a lot. Each unique "planet" is a different species.

The symbiotic diversity just around these two trees is remarkable. So which one came first, plants or fungi? Plants are autotrophs, while fungi are heterotrophs, so you think plants were independent and fungi jumped on board at a later date. Yet vesicle structures have been observed in 400 million year-old fossilized roots from the very first vascular plants. Many gymnosperms, especially in the family Pinaceae, are obligate hosts to EM fungi, suggesting that the fungi was present during evolution. Additionally, by the time angiosperms evolved fungi had been around for a long time, surely attributing to the present mycorrhizal mutualism found in over 90% of flowering plants.

So, are plants or fungi “the mothers” of the forest? Many people believe trees are the mothers, and in some ways they are, as their physical dominance creates the environment for all other life to flourish. But would that old-growth tree still be there after centuries of abuse from abiotic and biotic influence without any help? Would the seed of that tree even have germinated way back when with such little energy reserves and leached soil nutrients? Would that species even be in existence? In most instances probably not, leading me to believe that all life, including us, is dependent on mycorrhizae, the true mother of the forest.

Devin-
Interesting considerations! Great trail of life forms from the big to small, and so colorful!

Well, I suppose that I'm "tree-centric", having been taught to identify the ecosystem assemblage by it's most prominent (in most cases, read "biggest") member. But I really do recognize the many roles that the entire plant and animal community play in an old-growth forest ecosystem. It is that breadth, that diversity, that over time provides the basis for the resilience that old-growth ecosystems have that enables them to 'weather' cyclic natural disturbances. Chicken or the egg? Doesn't matter to me, as long as they're all in it together! The word 'synergy' comes to mind...

I'm reminded by the 1990's discovery of an 'obligatory symbiont' that could have defined (back when we were trying to "define" old-growth) eastern old-growth species...it was a tiny little nubbin that appeared on the bark of a now forgotten species.

Also reminded of the association of ponderosa pine, kaibab squirrels, and an underground truffle that resulted in special designation surrounding Kaibab Squirrel habitat specific to the North Kaibab Plateau...still shows up on old maps. And of the grizzly beers (weasels, martins, etc.), the Clark's nutcracker, and white-bark pine in and around Yellowstone.

Very interesting topic. It reminds me of the problems created by non-native, invasive earthworms, which eat up the duff layer and reduce or eliminate the mycorrhizal environment that many plants (including trees) need.

Don-- was that a Freudian slip: "grizzly beers" ?? :)

Ray
Musta been, I was wearing my T-shirt from the Grinning Grizzly Brewery (we visited it in a recent tour of British Columbia's interior)! I'd think that the right container to order a grizzly beer would a 'growler'...
And how could I have missed the opportunity for pairing Kaibab squirrels with underground trifles? A squirrels' favorite subterranean dessert spot!
Don

Don- Thanks, you always have something insightful to say in your comments. Clarks-nutcracker is a great example of symbiosis. I heard they were inoculating white bark pine with the slippery jack (Suillus sibiricus) in attempts to combat white pine blister rust. I hope it helps.

Ray- That makes sense, good point. I dont know much about exotic earthworms but I have seen the thread on this website.

http://www.sciencedaily.com/releases/20 ... 121950.htm

"Eissenstat explained that to grow, the thick-root trees use a close symbiotic association with mycorrhizal fungi in soils to take up nutrients, while the trees with thinner, more extensive roots are less dependent on the fungi. However, the ensuing root-foraging efficiency of the two ecological strategies is comparable."

Tree root research confirms that different morphologies produce similar results
Date:
June 9, 2015
Source:
Penn State
Summary:
Despite markedly different root morphologies and resulting disparities in nutrient-uptake processes, forest trees of different lineages show comparable efficiency in acquiring soil nutrients, according to researchers.